(a) Field of the Invention
The present invention relates to an improved circular stapler, and more specifically, to a circular stapler used for an operation of cutting off and suturing a jejunum, where a structure of a head section is improved to facilitate manipulation thereof and to enhance the potential for success of the operation.
(b) Description of the Related Art
In operations of suturing both cut-off ends, such as esophagus reconstruction after extracting the esophagus, gastrectomy, and small or large intestinal resection, studies and developments of operative methods and instruments for more completely anastomosing or suturing both cut-off ends have been carried out continually.
Specifically, in operations on insides of human bodies, there are many difficulties when anastomosing an end of an esophagus and a jejunum at positions where it is difficult to carry out specific manipulations inside a diaphragm after the above suturing operations, that is, total gastrectomy, or when cutting off a rectum up to a portion close to an anus and then anastomosing the large intestine and the remaining rectum each other. That is, in order to anastomose the esophagus and the jejunum after the total gastrectomy, a major operation of cutting ribs and the diaphragm to enter a chest should have been performed. In a case of operation on the rectum, the anus should have been removed and the large intestine should have been exposed to the abdomen, so that a disorder of receiving excrements should be left.
One of the operative instruments developed to overcome the operative difficulties is an intraluminal stapler, which is used for esophagus to jejunum anastomosis or intestine to intestine anastomosis, or cutting off a specific portion and anastomosing blood vessels each other. The intraluminal staplers are divided into circular staplers and linear staplers. The circular staplers are used mainly for anastomosing esophagus to jejunum in the total gastrectomy or anastomosing the jejuna each other and the linear staplers are used mainly for closing ends of cut intestines. Circular staplers having a diameter of 25 mm, 28 mm, 29 mm, 31 mm, 33 mm, etc. are put on the market.
Such a circular stapler is a product recognized officially by U.S. FDA (Food and Drug Administration), which is used as follows. An anvil is inserted into an upper end of the intestine to be anastomosed, the end of the intestine is tied, a cylindrical body having a head section including staples fixed in a circular shape and a cylindrical blade is inserted into a lower end of the intestine, a side surface of the intestine is pierced by a trocar tip, the trocar tip is coupled and fixed firmly to the anvil, the anvil and the head section come in close contact with each other and are stapled by turning an adjusting screw, and the intestines interposed therebetween are cut off, thereby anastomosing the ends of both intestines. A structure of the conventional circular stapler will be described in more detail with reference to U.S. Pat. No. 5,104,025.
U.S. Pat. No. 5,104,025, registered on Apr 14, 1992, discloses a conventional circular stapler having a detachable anvil. The circular stapler disclosed in FIG. 1 of the U.S. Pat. No. 5,104,025 is the same as the circular stapler 100 of FIG. 5. In FIG. 5, reference numerals, which are different from those of the circular stapler disclosed, in the U.S. Pat. No. 5,104,025, are used to explain the circular stapler 100 of a prior art for convenience. As shown in FIG. 5, the circular stapler 100 roughly comprises an anvil 10 and a cylindrical body 40, and the anvil 10 has a staple support 11 and an anvil shaft 21 and is detachably coupled to the cylindrical body 40. A trocar tip 22 passes through the cylindrical body 40, and a lower portion of the cylindrical body 40 is provided with a handle 50, a trigger 60, a safety 70 and an adjusting screw 80.
Although a method for using the circular stapler disclosed in U.S. Pat. No. 5,104,025 is not illustrated therein, such a circular stapler can be explained to be used hereinafter with reference to FIGS. 5 to 8.
A method of actually operating on the inside of a human body using the circular stapler is shown in FIGS. 6A to 6C. First, as shown in FIG. 6A, for example, A Rouxen Y method is used for anastomosing the esophagus to the jejunum after the total gastrectomy. At that time, a method of anastomosing an end of the esophagus to a side of the jejunum is used mainly for this operation. That is, the anvil 90 of the circular stapler is inserted into an end of the esophagus E to protrude the anvil shaft 92 outwardly, and then the lower portion is fixed temporarily with a thread. Next, the head section 94 of the circular stapler is inserted into an end of the jejunum J to be connected and the jejunum is bent, and then the trocar 93 is allowed to pierce the jejunum and to approach the anvil shaft 92.
Next, as shown in FIG. 6B, the anvil 90 and the head section 94 are connected by coupling the trocar tip to the anvil shaft 92, and the anvil 90 and the head section 94 become closer to each other by turning the adjusting screw provided at an end of the circular stapler, thereby allowing both to engage with each other. When the anvil 90 and the head section 94 come in close contact with each other, the safety of the circular stapler is released, the handle is grasped, and then the trigger is pressed. When the trigger is pressed, the cylindrical blade and the staples are projected from the head section 94, whereby the intestines between the anvil 90 and the head section 94 of the circular stapler are cut off and the end of the esophagus and the side of the jejunum are connected through the staples.
A state where the jejunum and the esophagus are anastomosed in this way is shown in FIG. 6C. After anastomosing the end of the esophagus E to the side of the jejunum J, the circular stapler is pulled out, and the opened portion of the jejunum J is sutured by stapling the opened portion with the linear stapler 910. As a result of this operation, the end of the esophagus is connected to the side surface of the jejunum to form a shape in which one tube is divided into two tubes, whereby only the portion through which food proceeding along the esophagus pass to proceed toward the lower portion of the jejunum is left opened.
Conventionally, since the portions to be connected of a human body could be easily connected using the above circular stapler to innovatively improve the operative methods, the complex operative processes are simplified very much and leakage from the anastomosed portion or the number of bleeding times are reduced, thereby considerably lowering the complication after operation and the mortality rate during operation. However, the conventional circular stapler causes several severe problems in the esophagus to jejunum anastomosis due to its structural features. These problems will be described in more detail with reference to FIG. 7.
(A) through (C) of FIG. 7 conceptually illustrate variation in diameter of the jejunum before and after performing the esophagus E to jejunum J anastomosis using the conventional circular stapler. Here, (A) of FIG. 7 schematically shows the shape of the jejunum before the operation, where point A is a portion which should be pierced by the circular stapler and which should be connected to the center of the esophagus. As shown in (A) of FIG. 7, the jejunum before the operation has almost the same inner diameter, where L1≈L2≈L3.
In this way, by inserting the head section 94 into the end of the jejunum J, piercing the side surface of the jejunum J with the trocar tip 93, and thus connecting the jejunum to the esophagus E, the state shown in (B) of FIG. 7 is obtained. That is, when the circular stapler having a cylinder-shaped head section 94 is inserted into the jejunum J, the circular stapler is tightly fitted to the inside of the jejunum J, and in this state, in order to connect the jejunum to the end of the esophagus E, the jejunum J should be bent at about 180° and a portion to be stapled by the circular stapler should be exposed. At that time, one end of the jejunum into which the circular stapler is inserted holds a circular sectional shape, while the other end of the jejunum through which food should actually pass is drawn due to application of tension. The end of the esophagus E is anastomosed to the jejunum by carrying out the stapling.
As shown in (B) of FIG. 7, when the head section 94 of the circular stapler is connected to the esophagus E, force is applied toward the top end of the head section 94 of the circular stapler and thus the tension on the jejunum is applied upwardly, so that a portion AB is stretched more than a portion A′B′ due to the tension. If the esophagus E is connected to the jejunum J in a state where the portion AB is abnormally stretched more than the portion A′B′ as described above, the state shown in (C) of FIG. 7 is obtained, so that the diameter L1 (length of AA″) of the jejunum to be restored to the original state is too small and may be rather closed. That is, since L1 is still shorter than L2 (length of BB′) and L3 (length of CC′), food passing through the esophagus does not proceed to the left jejunum for digestion, proceeds to the right jejunum, and is stored in the closed portion, it is easy to cause indigestion and the potential for sequela is large even after the operation.
Furthermore, in the anastomosed portion of the esophagus, the tension is applied uniformly on its circular section and the staples are uniformly distributed, but since the tension on the anastomosed portion in the side surfaces of the jejunum is not uniform and the anastomosed portion of the jejunum is stapled in a state where the AC side is more stretched than the AB side, relatively more jejunum tissues are stapled at the AB side. A proper tension is applied to point B. Therefore, the bleeding is much generated at an intermediate position between A and B. The non-uniform tension may constrict the anastomosed portion.
Specifically, the above problem may become severer because in most surgical operations, the operation wounds are invisible and senses of hands is absolutely relied on, and still severer because most surgeons do not consider the above problems as problems particular to the conventional circular staplers, but as their own technical mistakes.
On the other hand, (A) and (B) of FIG. 8 are conceptual diagrams illustrating another problem that may be caused in the operation using the conventional circular stapler. In actual operations, since the surgeons cannot see the shape of anastomosed wounds and handle the circular staplers only relying upon the sense of hands, the jejunum side through which food passes may be too folded and much relaxed, and may have a very large surface area compared with the circumference of the jejunum. As a result, the internal mucosa of the jejunum forming the folds may be interposed between the anvil 90 and the head section 94 and thus may be cut off.
That is, since the jejunum is severely constricted due to the technical mistakes as shown in (A) of FIG. 8 and portions not associated with the anastomosis are interposed between the anvil 90 and the head section 94 of the circular stapler and are cut off to form the shape shown in (B) of FIG. 8, the left side of the jejunum may be closed and thus a re-operation may be necessary.
This state may cause very severe complications. Since the inner diameter of the jejunum side through which food passes is very small, patients have difficulties in swallowing food. Further, since the tension of the anastomosed wound at the side of the jejunum is not uniform, the bleeding may be caused in the anastomosed wound and may be constricted.